The block-diagram level breakdown of the different sections of silicon is really a wonderfully helpful way to look at this. It makes the zoomed in view of each section more meaningful. Then seeing the die photo of individual transistors or groups of them, next to schematic level interpretation, really drives it home. Thanks for making something so instructive.

Have you decapped other sound-making devices? The greeting card chip makes me think of the ubiquitous "laser noise" chip from countless 80's kids toys. That or one of the many kid's keyboards or baby noise console devices, that have all of the function inside a single epoxy-blobbed die. It would be pretty fascinating to see a similar breakdown of which sections encode samples, note values, rhythm and sequences, control inputs, etc.